Combined air leak and valve for a sphygmomanometer



July 2, 1935. E. BANDOLY 2,006,878

COMBINED AIR LEAK AND VALVE FOR A SPHYGMOMANOMETER Filed Dec. 9, 1933 m INVENTOR 25 D .E'RJ'CH BANDOLY ATTORNEY Patented July 2, 1935 UNITED STATES PATENT orrics COMBINED AIR LEAK AND VALVE FOR A SPHYGMOMANORIETER Erich Bandoly, Rochester, N. Y., .assignor to Taylor Instrument Companies, Rochester, N. Y., a corporation of New York Application December 9, 1933, Serial No. 701,654

2 Claims. (Cl. 277-33) sure in the bandage by means of a suitable manometer. During the observations it is especially important that the physician may effect the release of air from the sleeve very slowly, especially when he is making the diastolic and systolic observations, or may release the air quickly after these observations have been made.

The main feature of the present invention relates to an adjustable air leak whereby air or other fiuid in a system may be released either quickly or under micrometer control, as desired by the operator.

A further feature of the invention relates to an impgroved combined air valve and adjustable air For a complete understanding of the principle of operation upon which the invention is based, its advantages and characteristic features, reference is made to the drawing wherein Fig. l is a face view of a sphygmomanometer incorporating the combined air leak and valve of the present invention; Fig. 2 is an enlarged sectional view of this combined air leak and valve; and Figs. 3 and 4 are greatly enlarged fragmentary sectional views useful in explaining the principle of operation of the air leak.

Referring to Fig. 1, 5 designates an inflatable sleeve or bandage applied to the arm 6 of the patient. The interior of this sleeve is connected through the tube 7 and combined air leak and valve 8, to the usual air bulb 9 and is also connected by tube In to any suitable type of manometer such as indicated at I In order to effect a satisfactory control of the passage of air to and from the sleeve 5, the combined air valve and leak 8 is provided. This valve as shown in detail in Fig. 2 comprises two separable, hollow parts l3 and I4 joined end to end, as indicated at |5 by a screw-threaded connection, to provide a main passageway through these parts. The part l3 terminates in a nipple I6 for connection with the tube 1 leading to the sleeve 5 while the part It is likewise provided with a bulb nipple H for connection with the air bulb 9. In

practice it is usually desirable to provide a suitable washer or gasket I8 between the parts |3 and H to prevent leakage of air through the joint between them. A dished plate |9 having openings 26 therethrough, rests against an annular shoulder 20 of the part I3, while a valve disc 2| of a material similar to patent leather normally rests against the annular shoulder 22 of the part l4, but is capable of limited motion as far as the face of the plate l9. It will be understood that when air is forced by the air bulb through the nipple H, the disc 2| is forced against the plate l9 so that air may pass around the edge of the disc, through the openings 26 in the plate and the opening in the nipple I6 to the tube 9 and thence to the sleeve 5. However, when the bulb 9 is no longer operated, the air pressure in the sleeve 5 and the tube 1 forces the disc 2| against the shoulder 22, to prevent the flow of air from the sleeve back to the bulb.

The part I3 has a second or air leak passageway extending at right angles to and communieating with the main air passageway through the valve. The flow of air through the air leak passageway is controlled by the air leak screw |2 which is threaded at its lower portion as indicated at 23 for engagement with the threaded recess 24 in the opposite wall of part l3, so that this screw is movable along the principal axis of this passageway. The screw at its intermediate portion has a single turn male thread 25, which may be likened toa valve disc inclined to its valve stem which thread is adapted to engage the corresponding female threaded portion 21 formed in the wall of the air leak passageway, which threaded portion may be considered as an inclined valve seat. It should be noted that the diameter of part 30 of the screw between the threaded portions 24 and 25 is less than the diameter of the roots of the threads of this portion.

The part I3 is also provided with the valve seat 28 to be engaged by the valve face 29 formed on the upper portion of the air leak screw. This valve face when engaging the valve seat 28 completely stops the escape of air from the sleeve 5. However, when the air leak screw is unscrewed so that the valve face 29 is out of engagement with the valve seat 28, air will gradually escape from the system through the imperfect joint between the male screw thread 25 and the corresponding female threaded part 21 of the body, depending on the adjustment of the screw from its closed position indicated in Fig. 3 to its open position illustrated in Fig. 4, wherein the helix angle of the male thread is indicated at H and the maximum opening of the leak is indicated by. the distance D. With the proper adjustment of the air leak screw. only infinitesimally small quantities of air will escape. However, when the male screw thread 24 disengages the female threads 21, air will escape quickly from the sleeve.

In the taking of blood pressure by means of the sp yzmomanometer herein disclosed, the sleeve 5 is first applied -to the patients arm in a position to obstruct the arterial flow of blood. The knurled screw I2 is turned to close the air leak completely. after which the air bulb 9 or other suitable pump is used to force air through the valve 8 and tube 1 to the interior of the sleeve 5 until the blood stream through the artery under observation, is completely stopped. The physician with the stethoscope applied to the patients arm over the portion of the mentioned artery below the sleeve, then turns the air leak screw H to permit air to exhaust slowly from the sleeve through the leak, while observing the manometer reading when the blood just starts to flow through the artery under observation. The air in the sleeve is further slowly released through the leak until the physician has taken the diastolic pressure reading. Thereafter the air in the sleeve is preferably exhausted quickly so that the sleeve can be immediately removed from the patient's arm as soon as the observations have been completed. By this novel air-leak, the flow of air from the sleeve is controlled at will from an amount just noticeable on the manometer to a prompt deflation of the sleeve.

aooems I claim:

1. An adjustable air leak comprising a body portion provided with a main passageway extending therethrough, said body portion having an opening therein. and a second passageway extending from said opening across said main passagewayto a point in the opposite wall of said body portion, the wall of said second passageway at each side of said main passageway being provided with female threaded portions, and a member provided with a part having a single turn male screw thread adjacent said opening and with a part having male screw threads spaced from said single thread, said threaded parts cooperatiriig respectively with said female threaded port ons.

2. An adjustable air leak comprising a body portion provided with a main passageway extending therethrough, said body portion having an opening therein and a second passageway extending from said opening across said main passageway to a point in the opposite wall of said body portion, the wall of said second passageway at each side of said main passageway being provided with female threaded portions and being also provided adjacent said opening with a valve seat, and a member provided with a valve, with a single turn male screw-threaded part adjacent said valve and with a male screw-threaded part spaced from said single threaded part to cooperate respectively with the valve seat and with said femalethreaded portions.

ERICH BANDOLY. 

